JP2013037204A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a full state of a waste toner by a single waste toner detection sensor without any error in an image forming apparatus.SOLUTION: The image forming apparatus is configured to transfer a toner image from a toner image carrier to an intermediate transfer body or paper and remove a waste toner from the toner image carrier. The image forming apparatus includes: a waste toner box 20 for collecting and storing the waste toner removed from the toner image carrier; an optical waste toner detection sensor 25 disposed in such a position to be shielded from light when an amount of the waste toner stored in the box 20 reaches a specific amount; and control means receiving a detection signal from the sensor 25. Even when receiving a waste toner detection signal from the sensor 25 immediately after ending an operation of collecting the waste toner in the box 20, the control means determines that the waste toner is not full in the box 20 and, only when receiving the waste toner detection signal from the sensor 25 after a specific time has passed from the end of the collecting operation, determines that the waste toner is full.

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus such as an electrophotographic copying machine or printer.

  In general, an electrophotographic image forming apparatus includes a waste toner collecting device that collects waste toner removed from a toner image carrier such as a photosensitive member or an intermediate transfer member, or waste developer removed from a developing device. ing. The collected waste toner is collected in a waste toner container, and the waste toner detection sensor detects whether or not the container is full of waste toner. When it is full, a message (warning) is displayed on the display panel, and the user or operator is instructed to remove the waste toner in the container.

  By the way, the waste toner detection sensor is an optical sensor, and the waste toner collected in the storage unit is scattered and floated in the storage unit immediately after the collection, and eventually in the bottom of the storage unit. Precipitate. Therefore, when waste toner is detected immediately after the end of the waste toner collection operation (for example, immediately after the end of the print operation or immediately after the end of the image stabilization operation), the optical sensor detects the waste toner in a floating state, There is a possibility that the container is not fully filled but is erroneously detected as full.

  In Patent Document 1, a scattered toner detection sensor is provided in a waste toner bottle, and when the scattered toner detection sensor detects the scattered toner when performing waste toner full detection control, input information of the full detection sensor is displayed. An image forming apparatus that is not detected is described. However, this apparatus has a problem that a scattered toner detection sensor is required, and the number of installed sensors increases.

JP 2006-285134 A

  An object of the present invention is to provide an image forming apparatus that can detect a full state of waste toner without mistake by a single waste toner detection sensor.

An image forming apparatus according to an aspect of the present invention is
In an image forming apparatus in which a toner image is transferred from a toner image carrier onto an intermediate transfer member or paper, and waste toner is removed from the toner image carrier.
A waste toner container that collects and stores waste toner removed from the toner image carrier;
An optical waste toner detecting means disposed at a position where the waste toner storage portion is shielded from light when a waste toner storage amount reaches a predetermined amount;
Control means for receiving a detection signal from the waste toner detection means;
With
The control unit determines that the waste toner storage unit is full of waste toner even if a waste toner detection signal is received from the waste toner detection unit immediately after the operation of collecting the waste toner in the waste toner storage unit is completed. And determining that the waste toner is full when a waste toner detection signal is received from the waste toner detection means after a lapse of a certain time from the end of the collection operation.
It is characterized by.

  In the image forming apparatus, when the waste toner collected in the storage unit is settled from a floating state in the storage unit, it is determined whether or not the storage unit is full of waste toner. Accordingly, the waste toner full state can be detected without error despite the use of a single waste toner detection means.

  According to the present invention, a full state of waste toner can be detected without error by a single waste toner detection sensor.

1 is a schematic configuration diagram illustrating a main part of an image forming apparatus. The waste toner storage box is shown, (A) is an external perspective view, (B) is a horizontal sectional view. FIG. 2 is a block diagram illustrating a main part of a control unit of the image forming apparatus. 4A and 4B are explanatory diagrams when collecting waste toner in the waste toner box, where FIG. 5A shows a case where the amount of accommodation is large, and FIG. 5B shows a case where the amount of accommodation is small. FIG. 6 is a flowchart illustrating a first control procedure regarding waste toner collection. FIG. 10 is a flowchart illustrating a second control procedure regarding waste toner collection.

  Embodiments of an image forming apparatus according to the present invention will be described below with reference to the accompanying drawings.

  The image forming apparatus shown in FIG. 1 is a tandem color image forming apparatus, in which toner images respectively formed on the photosensitive drums 2 included in the juxtaposed image forming units 1 are rotated in the direction of arrow A. The toner image is primarily transferred to the transfer belt 10 and synthesized, and the synthesized toner image is secondarily transferred onto a sheet (not shown) by the secondary transfer unit 15. Reference numerals y, m, c, and k attached to the reference numerals indicate members that form yellow, magenta, cyan, and black images, respectively.

  The image forming unit 1 is mainly composed of a photosensitive drum 2 and a developing device 3, and waste toner removed from the photosensitive drum 2 includes an old carrier removed from the developing device 3 through the transport pipe 4. The waste developer is transported through a transport pipe 5 to a waste toner container (hereinafter referred to as a waste toner box 20) shown in FIG.

  Further, a toner bottle 16 containing replenishing toner is installed immediately above the intermediate transfer belt 10. Residual toner on the intermediate transfer belt 10 is also removed by the cleaning unit 11, and waste toner from this portion is also stored in the waste toner box 20. A mechanism for transporting waste toner removed from the photosensitive drum 2 and the intermediate transfer belt 10 to the waste toner box 20 is well known in this type of image forming apparatus (for example, JP 2010-145812 A). See the official gazette).

  The waste toner box 20 is formed in a rectangular parallelepiped shape using a transparent resin as a raw material, and waste toner conveyed from the conveyance pipe 27 (see FIG. 4) is accommodated from the opening 21 on the upper surface. A detection portion 22 that protrudes outward is provided on an upper portion of one side of the box 20. Waste toner detection sensors 25 each including a light emitting unit 25a and a light receiving unit 25b are installed on both sides of the detection unit 22, respectively. The detector 22 is normally in a light transmissive state. When the waste toner collected in the box 20 is accumulated up to the detection unit 22 (when it becomes full), the sensor 25 is in a light-shielded state, and the box 20 is now full of waste toner. Detected. The box 20 only needs to be formed of a transparent material for the detection unit 22 and does not need to be entirely formed of a transparent material.

  FIG. 3 shows the control unit 40 of the image forming apparatus. The control unit 40 is configured with the CPU 41 as the center, and image data to be printed is transmitted from an external device 52 such as a scanner 51 or a computer. The CPU 41 receives a detection signal from the waste toner detection sensor 25 and the like. Further, the CPU 41 generally controls the image forming apparatus, instructs various displays on the display panel 55, and controls the operations of the image forming unit 1, the intermediate transfer belt 10, and the like.

  Incidentally, as shown in FIG. 4, the waste toner conveyed from the conveyance pipe 27 is scattered and floated immediately after being collected in the box 20. 4A shows the floating toner Tb when the amount of waste toner Ta already stored is relatively large, and FIG. 4B shows the floating toner Tb when the amount of waste toner Ta already stored is relatively small. Is shown. This type of floating toner Tb is generated immediately after the collecting operation and eventually settles at the bottom of the box 20.

  As shown in FIG. 4B, when the amount of the already-accommodated waste toner Ta is relatively small, the newly collected and scattered floating toner Tb does not reach the detection unit 22. However, as shown in FIG. 4A, when the amount of the already-accommodated waste toner Ta is relatively large (close to full), the newly collected and scattered floating toner Tb reaches the detection unit 22, and the sensor 25, a waste toner detection signal is output. That is, it is erroneously detected as full.

  In order to avoid the erroneous detection described above, in this embodiment, even if the CPU 41 receives a waste toner detection signal from the sensor 25 immediately after the operation of collecting the waste toner in the box 20, the box 20 is full of waste toner. If a waste toner detection signal is received from the sensor 25 after a predetermined time has elapsed since the end of the collection operation, it is determined that the waste toner is full. Immediately after the end of the collection operation is immediately after the end of the printing operation or immediately after the end of the image stabilization operation. The image stabilization operation means optimization control of image forming conditions (charging voltage, development bias, transfer voltage, etc.) by the image forming unit 1 and deviation adjustment control of each color toner image on the intermediate transfer belt 10. This is a conventionally known control.

  Further, when the CPU 41 receives a waste toner detection signal from the sensor 25 immediately after the end of the collection operation and receives a waste toner detection non-detection signal from the sensor 25 after a predetermined time has elapsed from the end of the collection operation. It is determined that the box 20 is almost full. The predetermined time may be changed according to the system speed (the rotational speed of the photosensitive drum 2 and the intermediate transfer belt 10), or according to the number of images to be continuously formed (number of prints in one job). It may be changed.

  Below, the 1st example (refer FIG. 5) and the 2nd example (refer FIG. 6) of the control procedure regarding waste toner collection by CPU41 are demonstrated.

  In the first example of the control procedure, as shown in FIG. 5, when a series of printing operations is completed (step S1), it is determined whether or not the sensor 25 has detected waste toner (step S2). For example, as shown in FIG. 4B, it means that the capacity of the box 20 is still sufficient, and this control is finished. If waste toner is detected in step S2, the passage of a fixed time is awaited (step S3), and it is determined again whether the sensor 25 has detected waste toner (step S4). The fixed time is, for example, 30 seconds, and is the time required for the floating toner Tb shown in FIG. The fact that the waste toner is detected in step S4 means that the waste toner Ta that is precipitated by the sensor 25 instead of the floating toner Tb has reached the detection position of the sensor 25. Therefore, here, it is determined that the box 20 is full of waste toner (step S5), and a warning is displayed on the display panel 55 that "the box 20 is full of waste toner and the box 20 is to be replaced" (step S5). S6) Printing is prohibited (step S7).

  On the other hand, if the waste toner is not detected by the sensor 25 at the time of detection again in step S4, it means that the floating toner has settled below the sensor 25. In this case, the box 20 is not full of waste toner but is almost full. Here, the display panel 55 displays “near full” (step S8), and preparation of the new box 20 is performed. Instruct.

  Incidentally, the amount of the floating toner Tb varies depending on the system speed and the series of prints. When the system speed is high and the number of printed sheets is large, the amount of floating toner Tb increases and it takes time to settle. Therefore, in the second example of the control procedure, the standby time until the detection is performed again is changed according to the system speed and the number of prints. The standard system speed is 30 sheets per minute, the standby time in that case is 30 seconds, the standby time is set longer when the system speed is faster than the standard, and the standby time is set shorter when the system speed is slower. The standard number of prints is set to 15 for one job, and the waiting time in that case is set to 30 seconds. If the number of printed sheets is larger than the standard, the waiting time is set longer, and if the number is smaller, the waiting time is set shorter.

  Specifically, as shown in FIG. 6, when a series of printing operations is completed (step S11), it is determined whether or not the sensor 25 detects waste toner (step S12). As shown in FIG. 4B, this means that there is still room in the capacity of the box 20, and this control is terminated. If waste toner is detected in step S12, it is determined whether the system speed is high (step S13) or whether the number of prints is large (steps S14, S15). When the system speed is high and the number of prints is large (YES in steps S13 and S14), the standby time is set to T1 (for example, 50 seconds). If the system speed is fast and the number of prints is small (YES in step S13, NO in step S14), and if the system speed is slow and the number of prints is large (NO in step S13, YES in step S15), the standby time is set. Set to T2 (for example, 30 seconds). When the system speed is slow and the number of printed sheets is small (NO in steps S13 and S15), the standby time is set to T3 (for example, 10 seconds).

  Thereafter, in steps S16, S17, and S18, the passage of the respective waiting times T1, T2, and T3 is waited, and it is determined again whether the sensor 25 has detected waste toner (step S19). The fact that the waste toner is detected in step S19 means that the waste toner Ta that has settled instead of the floating toner Tb has reached the detection position of the sensor 25. Therefore, it is determined here that the box 20 is full of waste toner (step S20), and a warning is displayed on the display panel 55 that "the box 20 is full of waste toner and the box 20 is to be replaced" (step S20). S21), printing is prohibited (step S22).

  On the other hand, if the waste toner is not detected by the sensor 25 at the time of detection again in step S19, it means that the floating toner has settled below the sensor 25. In this case, the box 20 is not full of waste toner but is almost full. Here, the display panel 55 displays “near full” (step S23), and preparation of the new box 20 is performed. Instruct.

  Note that the image forming apparatus according to the present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the gist thereof.

  In particular, the configuration of the image forming portion by the electrophotographic method is arbitrary, and a monochrome printer may be used. Further, the detailed configuration of the waste toner container and the arrangement of the waste toner detection means are arbitrary.

  As described above, the present invention is useful for an image forming apparatus, and is particularly excellent in that a full state of waste toner can be detected without error by a single waste toner detection sensor.

DESCRIPTION OF SYMBOLS 1 ... Image forming unit 2 ... Photoconductor drum 10 ... Intermediate transfer belt 20 ... Waste toner box 25 ... Waste toner detection sensor 41 ... CPU

Claims (6)

In an image forming apparatus in which a toner image is transferred from a toner image carrier onto an intermediate transfer member or paper, and waste toner is removed from the toner image carrier.
A waste toner container that collects and stores waste toner removed from the toner image carrier;
An optical waste toner detecting means disposed at a position where the waste toner storage portion is shielded from light when a waste toner storage amount reaches a predetermined amount;
Control means for receiving a detection signal from the waste toner detection means;
With
The control unit determines that the waste toner storage unit is full of waste toner even if a waste toner detection signal is received from the waste toner detection unit immediately after the operation of collecting the waste toner in the waste toner storage unit is completed. And determining that the waste toner is full when a waste toner detection signal is received from the waste toner detection means after a lapse of a certain time from the end of the collection operation.
An image forming apparatus.   The image forming apparatus according to claim 1, wherein the immediately after the collection operation is immediately after the end of the printing operation.   The image forming apparatus according to claim 1, wherein the time immediately after the end of the collecting operation is immediately after the end of the image stabilization operation.   4. The image forming apparatus according to claim 1, wherein the predetermined time is changed according to a system speed.   4. The image forming apparatus according to claim 1, wherein the predetermined time is changed according to the number of sheets on which images are continuously formed.   The control means receives a waste toner detection signal from the waste toner detection means immediately after the end of the collection operation, and outputs a waste toner detection non-detection signal from the waste toner detection means after a lapse of a certain time from the end of the collection operation. 6. The image forming apparatus according to claim 1, wherein when it is received, the waste toner container is determined to be almost full.

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